After assembly, test the engine before installing the engine in the vehicle if possible. If a test stand is not available, use the following procedure:

1. Fill the crankcase with oil.
2. If a new camshaft and lifters have been installed, add engine oil supplement GM P/N 1052367 to the engine oil.
3. Fill the cooling system with coolant.
4. Add cooling system sealing pellets GM P/N 3634621 to the engine cooling system.

•	Add the pellets directly to the radiator or pressurized coolant reservoir on systems that do not have caps on the radiator.

•	Crush the pellets before installation.

5. Crank the engine several times and listen for unusual noises or any other evidence of mechanical problems.
6. Start the engine.
7. Listen for any abnormal engine sounds.
8. Run the engine at 1,000 RPM until the engine is at operating temperature.
9. After the engine is at operating temperature, shut the engine off.
10. Inspect the engine carefully for oil or coolant leaks.